is_allowed_to_work fixed for empty task_worker
is_allowed_to_work fixed for empty task_worker

crowdresearch/daemo,crowdresearch/crowdsource-platform,shirishgoyal/crowdsource-platform,crowdresearch/daemo,crowdresearch/daemo,crowdresearch/daemo,crowdresearch/crowdsource-platform,shirishgoyal/crowdsource-platform,shirishgoyal/crowdsource-platform,crowdresearch/crowdsource-platform,shirishgoyal/crowdsource-platform,crowdresearch/crowdsource-platform